Things have got rather confusing and the good folk at proDAD thought I was a registered user when in fact I am trying to get the trial to work before doing anything else. This meant that the link I'd been sent was to the "official" version of the software which I was unable to install, naturally enough, because I don't have a serial number. Anyway, an email resolved that and I'm now up and running again with the trial version and I can continue my labours.

I was sent this information earlier on so I have now removed the CCCP codec pack and have followed these instructions, as provided by proDAD support:

The Video-Codec at this system transfers the data erroneous to Mercalli, for which reason the loading failed. A possible solution could be to install a free available Codec-Pack such as following:
1.First of all please install this package*
http://www.prodad.de/support/files/MatroskaSplitter-32bit.exe
2. Then please install this package*
http://www.prodad.de/support/files/ffdshow-32bit-sse.exe
Now please try to load the video file again.

The current position is that I have successfully loaded a very short video clip into the Mercalli package which analysed fine and I then exported it as an AVI file, so far so good, but I've been here before.

I have now loaded a 47 minute MOV clip which is currently analysing and I expect that to work fine, the big test comes when I try to export it, I expect it to sit at 0% and do nothing, I'll let you know!